Tele Vue 102iis Imaging System 4" f/8.6 2 Element APO Refractor Optical Tube Assembly, Ivory

Concept:
CCD cameras have challenged telescope optics beyond anything ever placed at the focal plane. Tele Vue knew it's APO objectives were up to the challenge, & with the proper tweaks would be extraordinary tools for the imager. With Tele Vue Imaging System (is) telescopes, they have refined their instruments & optional equipment beyond anything a CCD chip has seen.

It started small (literally) in 2005 with the Tele Vue-60is & available Digital Micrometer Kit. Achieving critical acclaim with the 60is, Tele Vue was encouraged to further develop "is" telescopes & accessories to maximize aperture, real field coverage & performance, & to make the processes easier for the imager.

For 25 years, Tele Vue has pushed the boundaries of APO refractors, & eyepieces, to the recognized pinnacle of performance. They were gratified but not surprised that Backyard Astronomer's Guide said of the NP101: "optics don't get any better than this." No wonder "Sky and Telescope" rated the NP101 tops & selected it as the test instrument for its landmark review of the SBIG STL-11000 CCD camera.

The "is" versions of the Tele Vue- 60, 102i, NP101 & NP127 retain the exemplary wide field & planetary visual capability while adding new features to make imaging easier & more flexible.

Tele Vue-102iis:
Need back focus? The Tele Vue-102iis has it. Typically, reducer/correctors for doublet or triplet refractors swallow precious back focus which could otherwise be used for accessories. Since the Tele Vue-102iis is the Imaging System version of the Bino Vue ready 102i, the short tube provides the imager with nearly 5" of back focus with the 0.8x reducer/ flattener in place!

Visually, the 102iis functions at its native 880mm, f/8.6 for 1x Bino Vue use. Astrophotography requires the use of the dedicated 0.8x reducer/ flattener, yielding a 704mm, f/6.9 system. The 4" APO-doublet objective makes the 102iis one of the least expensive, multi-purpose, high performance, scopes available in its aperture class.

Mechanically, the Tele Vue-102iis features the large 2.4" focuser. The non-vignetting focuser prevents any restriction of the converging light cone. The draw tube has a 3" front aperture & 2.4" rear aperture. This new draw tube also permits quick change from visual to imaging operation & allows full camera rotation without focus change. In addition, it has the capability to correct for any residual focal plane tilt & accepts a "position stop" for our digital micrometer to allow repeatable focus measurement to 0.0001".

To maintain squareness to the optical axis while changing camera orientation, the draw tube has four lock screws that tighten against a taper on the "imaging insert" ring. This insert is, in turn, threaded to accept Tele Vue's new Imaging System series of accessories including large diameter extension tubes, optical accessories, and camera and CCD attachments, all with mating threads.